The invention relates to cutting devices and more particularly to a cutting device that accepts programmable control instructions to produce wooden construction components of various designs.
Such various designs include without limitation the saw-tooth pattern of wooden stair stringers (not shown), or the components of wooden trusses and so on. FIG. 1 shows a representative gable truss 20. Nowadays these assemblies 20 as well as their wooden components are mass produced in assembly line fashion. This truss 20 comprises a straight bottom chord 22, a symmetric pattern of assorted webs 23, an opposite pair of inclined top chords 24, and then all the junctions therebetween are fixed together by pressed-in nail plates 25. The top chords 24 have bottom ends formed with a seat 27 and a butt 28 (eg., as in for abutting a stop).
It is popular to cut the seat 27 and butt 28 with a saw machine (not shown). To do so in optimized mass-production fashion, preferably the saw machine will have two circular saws stationed at different stations relative the longitudinal run of the conveyance path. Lumber stock is sawed as it is conveyed past the saw stations.
The lumber stock is typically conveyed along the conveyance path in the following fashion. Briefly, a single board is understood needless to say as being elongated between two spaced ends and having two opposite broad sides (eg., indicated by reference character B in FIG. 2) between two opposite narrow sides (eg., indicated by reference character N in FIG. 2). Hence, a single board will be stood erect on one narrow side N, advancing forward down the longitudinal run with one broad side B leading, the opposite ends being carried along spaced longitudinal lanes on the opposite lateral sides of the conveyance path. A succession of boards will appear like flights on a flight conveyor. By conveying the lumber stock this way, the board ends hang out over the opposite lateral edges of the conveyance path, and can be conveyed past work stations where, among other things, they might be conveyed past waiting circular-saw blades.
Ordinarily, both circular saws on a saw machine will be adjustable such that their drive spindles can be inclined in various angles in a lateral plane. To cut the seat 27, one saw blade will have to be oriented to spin a plane angled about 20° up from the horizontal. To cut the butt 20, the other saw blade will have to be adjusted about plus 90° relative to the one saw blade, or in sum to about a 110° angle if measured from the same horizon as used to measure the 20° angle. Thus resultant seat 27 and butt 28 intersection is about 90°.
FIG. 2 shows an alternative wooden truss design 30, as for a cathedral ceiling. It comprises an opposite pair of in inclined bottom chords 32 and then a more steeply-inclined opposite pair of top chords 34. FIG. 3 is enlarged view of the top chord 34's bottom end. Like FIG. 1, it comprises a seat 37 and butt 38. Unlike FIG. 1, this top chord 34 further comprises a scarf 39. Now, the aforementioned saw machines have been further adapted to handle this design. That is, in order to maintain optimized mass production, preferably such a saw machine will have three saws instead of two: a first for the seat 37, a second for the butt 38 and the third for the scarf 39.
There are various shortcomings with the prior art saw machines. One is that, if the scarf 39 measures nearly two feet in length (−60 cm), then the circular saw for the scarf cut will have a blade that measures at least five feet in diameter (−150 cm). Other shortcomings include without limitation that circular saws are fairly limited to producing straight line cuts.
It is an object of the invention to overcome various shortcomings with the prior art.
A number of additional features and objects will be apparent in connection with the following discussion of preferred embodiments and examples.